The NFL's collective bargaining agreement forces players to take baby steps through the offseason, limiting their activity in precise stages until climaxing with veteran minicamps.

Still, Andrew Luck and the Colts are trying to maximize their opportunities, using the current stage in which limited on-field work is permitted to their fullest advantage.

So, this week at the Colts' training facility, Luck could be found running the offense and trying to perfect the system — even if something obvious was missing.

"We're not going against the defense, per CBA rules," Luck said. "But we're allowed to run plays on air, working on our different styles of offense, working on route timing. That's probably the biggest focus, with the wideouts, tight ends and running backs. It's been really productive."

The Colts and other NFL teams can accelerate their on-field work beginning next week when organized team activities (OTAs) begin. Ten such practices are allowed, with offenses and defenses pitted against one another.

But for now, there's still much to be gained in spite of the restrictions. The Colts are integrating receiver Hakeem Nicks, signed in free agency this spring, and re-integrating tight end Dwayne Allen, who played just two games in 2013 because of a season-ending hip injury.

Reps of any kind can help them as well as young players still trying to fully grasp coordinator Pep Hamilton's offense.

"It is very beneficial to go (against) air," Luck said. "The timing especially. As I've figured out in my short time in this league, timing is very, very important. People are very fast and that ball better be up and down. Those wideouts, they know how to get open and it's up to (quarterbacks) to get them the ball."

Allen is sure to be on the other end of some of those passes from Luck. After missing so much time last year, he's been healthy enough to participate in the on-field drills the offense is conducting. Turns out, he needs it.

"It takes that everyday grind to really come back," said Allen, who caught 45 passes as a rookie in 2012. "I've really had to teach myself how to run again. Once I got back going after the first couple of days, it was getting back into my timing with the quarterback. But it's going well. It's getting better and it's about not getting discouraged when you have a setback."

And next week, when the defense — equally anxious to match up — joins the party, things could get really interesting.